1. Field of the Invention
The present invention relates to a receiving apparatus, and in particular to an apparatus and a method for receiving contents data which is distributed via a network.
2. Related Background Art
It is becoming possible to supply contents including audio and video via the Internet as a program, which have been supplied by means of ground waves, satellite waves, or cables.
In the conventional broadcast using radio waves or through cables, it is possible for a user to audio visually enjoy a program immediately when the user satisfies conditions necessary for reception and selects a broadcast in a receiver. A transmission quality is hardly affected by an increase or decrease of users, who are simultaneously audio visually enjoying a program, owing to characteristics of a transmission line.
On the other hand, in the world of the Internet, by connecting a server to the Internet, contents can be supplied to an unspecified member of general public as a program.
In the Internet environment according to a best effort type service, a response speed of a site varies depending upon a constitution of the site or an operating state of the site at every moment. That is, since a site providing a service has to respond to each request for the service individually, it is likely that a response speed for an individual access for contents provided by the site is delayed if a large number of users use the contents simultaneously or other load on the site is large. In some cases, the users may not be able to receive the service itself depending upon a degree of congestion.
In addition, a transfer speed of data for access varies depending upon a state of a network between a contents supply site and a receiver of a user. Moreover, a data path on the network is not always fixed. A transfer path may change to cause a change in a response speed or a transfer speed of contents data.
Examples of a related art include Japanese Patent Application Laid-Open Nos. H11-234581, H11-275477, and 2001-309258.
As described above, in the case in which a service via the Internet is offered, a response speed or a transfer speed of contents to be provided may change. In the case in which a program made of stream data involving video and audio is used as a service, this speed is recognized as a necessary period until the program becomes actually audio visually enjoyable after the program is selected. For example, a necessary period until audio visual enjoying is started changes depending upon a state of a site on a network. An audience does not know the necessary period until the audience selects a program and actually accesses a site of the program. Therefore, under a situation in which sites having various response abilities are mixed and the state changes every moment on the network, the audience is kept waiting, without knowing how long he/she would be actually kept waiting, until reproduction of video and audio is actually started after the audience selects a program. The audience feels uneasiness about waiting for an unpredictable time, which causes significant stress for the audience in using the service.